pyo3/types/
none.rs

1use crate::ffi_ptr_ext::FfiPtrExt;
2use crate::{ffi, types::any::PyAnyMethods, Borrowed, Bound, PyAny, PyObject, PyTypeInfo, Python};
3#[allow(deprecated)]
4use crate::{IntoPy, ToPyObject};
5
6/// Represents the Python `None` object.
7///
8/// Values of this type are accessed via PyO3's smart pointers, e.g. as
9/// [`Py<PyNone>`][crate::Py] or [`Bound<'py, PyNone>`][Bound].
10#[repr(transparent)]
11pub struct PyNone(PyAny);
12
13pyobject_native_type_named!(PyNone);
14
15impl PyNone {
16    /// Returns the `None` object.
17    #[inline]
18    pub fn get(py: Python<'_>) -> Borrowed<'_, '_, PyNone> {
19        unsafe { ffi::Py_None().assume_borrowed(py).downcast_unchecked() }
20    }
21
22    /// Deprecated name for [`PyNone::get`].
23    #[deprecated(since = "0.23.0", note = "renamed to `PyNone::get`")]
24    #[inline]
25    pub fn get_bound(py: Python<'_>) -> Borrowed<'_, '_, PyNone> {
26        Self::get(py)
27    }
28}
29
30unsafe impl PyTypeInfo for PyNone {
31    const NAME: &'static str = "NoneType";
32
33    const MODULE: Option<&'static str> = None;
34
35    fn type_object_raw(_py: Python<'_>) -> *mut ffi::PyTypeObject {
36        unsafe { ffi::Py_TYPE(ffi::Py_None()) }
37    }
38
39    #[inline]
40    fn is_type_of(object: &Bound<'_, PyAny>) -> bool {
41        // NoneType is not usable as a base type
42        Self::is_exact_type_of(object)
43    }
44
45    #[inline]
46    fn is_exact_type_of(object: &Bound<'_, PyAny>) -> bool {
47        object.is(&**Self::get(object.py()))
48    }
49}
50
51/// `()` is converted to Python `None`.
52#[allow(deprecated)]
53impl ToPyObject for () {
54    fn to_object(&self, py: Python<'_>) -> PyObject {
55        PyNone::get(py).into_py(py)
56    }
57}
58
59#[allow(deprecated)]
60impl IntoPy<PyObject> for () {
61    #[inline]
62    fn into_py(self, py: Python<'_>) -> PyObject {
63        PyNone::get(py).into_py(py)
64    }
65}
66
67#[cfg(test)]
68mod tests {
69    use crate::types::any::PyAnyMethods;
70    use crate::types::{PyDict, PyNone};
71    use crate::{PyObject, PyTypeInfo, Python};
72
73    #[test]
74    fn test_none_is_itself() {
75        Python::with_gil(|py| {
76            assert!(PyNone::get(py).is_instance_of::<PyNone>());
77            assert!(PyNone::get(py).is_exact_instance_of::<PyNone>());
78        })
79    }
80
81    #[test]
82    fn test_none_type_object_consistent() {
83        Python::with_gil(|py| {
84            assert!(PyNone::get(py).get_type().is(&PyNone::type_object(py)));
85        })
86    }
87
88    #[test]
89    fn test_none_is_none() {
90        Python::with_gil(|py| {
91            assert!(PyNone::get(py).downcast::<PyNone>().unwrap().is_none());
92        })
93    }
94
95    #[test]
96    #[allow(deprecated)]
97    fn test_unit_to_object_is_none() {
98        use crate::ToPyObject;
99        Python::with_gil(|py| {
100            assert!(().to_object(py).downcast_bound::<PyNone>(py).is_ok());
101        })
102    }
103
104    #[test]
105    #[allow(deprecated)]
106    fn test_unit_into_py_is_none() {
107        use crate::IntoPy;
108        Python::with_gil(|py| {
109            let obj: PyObject = ().into_py(py);
110            assert!(obj.downcast_bound::<PyNone>(py).is_ok());
111        })
112    }
113
114    #[test]
115    fn test_dict_is_not_none() {
116        Python::with_gil(|py| {
117            assert!(PyDict::new(py).downcast::<PyNone>().is_err());
118        })
119    }
120}
pyo3/types/none.rs

pyo3/types/
none.rs
